The invention is aimed to solve technical problem of a realization of flight in extended speed diapason producing a required value force in any direction, including lift force for compensation of weight, on air rotors in mainly axial airflow owing to increased efficacy of producing lift and transversal rotor forces in additional to thrust, also in extended diapason of rotor axe inclination to air flow and control of rotor force value and direction owing to variation of thrust and lift rotor air force ratio in wide diapason for various flight mode, also for maneuvering with acceleration. Said problem is solved owing to that in method of flight in extended speed range, using thrust vectoring propellers.
There are known aircrafts using main rotors for flight. Helicopters belong to such a type of aircrafts.
Helicopter is an aircraft rising in the air using one or several propellers pulling it upwards, the propellers are being driven by an engine (B. N. Jurjev, Aerodynamic calculation of helicopters, Oborongiz, 1956, p. 40).
The axis of the main rotor and the device as a whole are inclined forward, and then the drawing force of main rotors T gives the pulling effort X resulting to moving the device. If inclining the machine aside or backwards it is possible to obtain lateral motion and reverse motion (B. N. Jurjev, Aerodynamic calculation of helicopters, Oborongiz, 1956, p. 109).
The inclination of the main rotor of a helicopter is being done using a special device named the wobble plate. This device invented and developed by academician B. N. Jurjev in 1911, is applied in all the modern helicopters (E. I. Ruzhitsky, Vertical take-off aviation, National publishing house of defense industry, Moscow, 1959, p. 71).
Turning the external ring of the wobble plate leads to turn of the internal rotating ring which comes in harmonic oscillation and forces to oscillate the blades about their longitudinal axes. The blade will run one part of the circle with a larger angle of incidence, than the other part, and, hence, the thrust of one half of disk would be higher, than the other (B. N. Jurjev, Aerodynamic calculation of helicopters, Oborongiz, 1956, p. 86).
Using such a method of control for main rotors allows to change the angle of the propeller axis and, accordingly, the direction of vectorial force of the propeller directed transversely to the propeller rotation plane.
The helicopter propeller is located in the horizontal plane and it is being blown in flight by the airflow in the direction close to a the rotation plane that leads to changing the speed of ambient velocity of the coming blade as compared to that of the parting one.
The increase of the maximal speed of flight is limited, mainly, due to the phenomena of stalling on the blade going against the direction of flight and besides, due to the phenomenon of compressibility on the blade going in the direction of flight (E. I. Ruzhitsky, Vertical take-off aviation, National publishing house of defense industry, Moscow, 1959, p. 95).
There are known screw propellers. Those propellers are designed to impart the devices on which they are mounted, to get a translational motion in the direction either conterminous or close to the direction of the axis of their rotation (B. N. Jurjev, Aerodynamic calculation of helicopters, Oborongiz, 1956, p. 50).
The screw propellers may be used in a wide range of speeds as the plane of the propeller is transversal to the stream and there is no nonuniformity of the streamline of blades.
The increase of thrust of the air propeller due to increase of rotational speed is limited by the increase of profile resistance of blades.
There are propellers with a fixed pitch and propellers with adjustable pitch having the blades that may turn in flight about their axes (Aircraft designer directory, Vol. 1, ZAGI, 1937, p. 175).
The advantages of adjustable pitch propeller as compared to the fixed pitch propeller grow at the same time as the range of flight speed increases as the range of angles of incidence of the blades necessary for getting the full power also grows (Aircraft designer directory, Vol. 1, ZAGI, 1937, p. 206).
The increase in rotational speed of screw propellers is limited due to losses connected with compressibility, therefore when increasing the speed of flight the amount of relative speed grows and verges to unity thus defining the amount of advance ratio for air propellers used in aircraft in the range:λ=0÷3.5,
Where λ is the advance ratio of the air propeller.
When flying at high speeds as increasing the advance ratio of the propeller the angles of incidence of the blades are also increased for maintaining the angles of attack of blades, thus the forces created by the propeller blades deviate closer to the plane of rotation, and the losses for swirling the airflow behind the propeller grow.
There is another drawback inherent to propellers used in aircraft: when flying at high speeds they cannot create elevating force for balancing of masses in flight, thus they are used only for creating the thrust.
From the patent literature there is known an aircraft for vertical and horizontal flight, U.S. Pat. No. 2,444,781, B64C29/00, containing a fuselage, one propeller consisting of four equal sized blades and rotating about an axis, aligned with the axis of the fuselage. The propeller is located near the centre of gravity of an aircraft. The aircraft has no wings, but it has wing and vertical fin surfaces for transition from vertical flight to horizontal flight, as well as for control of the aircraft position in flight.
In the same patent a method of flight using the above described aircraft is described. For creating the force, transversal to the axis of the propeller, it is necessary to incline the axis of the propeller in horizontal flight under a small angle to the direction of flight. Therefore, the effective angle of attack changes with according to the angular position of the blade. The angle of attack reaches the maximal value when the blade is horizontal, and becomes zero when the blade is vertical. In horizontal flight it is offered to use a rotating crosswise the screw wing when creating the draft and the torsional moment by jet engines at the ends of screw wings.
Similar development were carried out by other authors using direct-flow jet engines at the ends of blades.
The above aircraft and its method of flight have the following drawbacks.
In the above method at flight at a significant horizontal axial speed, as a result of axial pitch in the vertical plane, the forces directed upwards arise on the wing-blade rotating downwards and on the wing-blade rotating upwards. Therefore, the blades rotating upwards, create forces diminishing the speed. As a result of such a use the propeller creates elevating force,                however it does not create thrust, but creates resistance that leads to unjustified expenses of energy for creating thrust for overcoming the force diminishing the speed of the blade rotating upwards by jet engines, mounted at the ends of wings-blades while the thrust and elevating force may be created on the propeller.        
Another drawback of the above method of flight is the significant moment transversal to axes of the propeller effecting on the propeller, which should be compensated aerodynamic rudders.
The drawback of the method of creation of elevating force used for flight, transversal to the axis of rotation of the propeller, when the axis is inclined under a small angle to the incident flow, for example, in the vertical plane in horizontal flight, is that in case of rotation under wide angles to the horizontal position and blades close to vertical position the forces created on blades increase the thrust of the propeller, but do not make important contribution to create the lift.
In a number of applications an opportunity of use of coaxial propellers of opposite rotation located near the center of mass, for vertical take-off and flight of an aircraft was considered. Thus the vertical arrangement of the fuselage was used in the take-off and landing phases, while the further horizontal flight at significant speed was carried out due to mounting the propellers under a small angle of the axis to the direction of flight for creating lift and thrust.
One of such aircrafts, U.S. Pat. No. 2,328,786, B64C29/02, B64C29/00, is supplied with a pair of oppositely rotating two-bladed propellers with the axes aligned with the axis of the fuselage. The aircraft is supplied with empennage used for controlling the aircraft position, and with a power-plant bringing propellers to rotation.
To create the thrust necessary for take-off, the blades are rotating in a horizontal plane. After take-off and climb the aircraft gets over to a position for horizontal flight. In this mode of flight the blades rotate in the vertical plane and operate, as propellers of an aircraft flying forward, but at the same time the blades provide the lift for sustaining the aircraft in the air.
The main advantage of the aircrafts using propellers in the axial mode of flow is the absence of strongly pronounced nonuniformity of speeds when rotating the propeller blades. The moments coming to the aircraft from propellers of opposite rotation, laying in the plane of rotation and transversally to planes of rotation of propellers, come to balance.
The main problem of aircrafts using for flight the force transversal to the axis of propellers being in conditions close to axial flow, is creation of lift sufficient for flight and deflection of propeller force upwards, as well as impossibility to incline the axis at wide angles of attack at high speeds of flight.
In the above mentioned patent the conditions of creation of lift of sufficient value, the conditions of its adjustment and provision of absence of the phenomena of shock stall on propeller blades are not determined. Besides the conditions allowing to achieve the absence of sectors where blades are flowed under negative angles of attack are not determined.
The drawback of the method of creation of elevating force used for flight, transversal to the axis of rotation of the propeller, when the axis is inclined under a small angle to the incident flow, for example, in the vertical plane in horizontal flight, is that in case of rotation under wide angles to the horizontal position and blades close to vertical position the forces created on blades increase the thrust of the propeller, but do not make important contribution to create the lift.
There is also known an aircraft of a partly convertible type, U.S. Pat. No. 4,123,018, B64C29/02, B64C29/00, B64C27/10, having, at least, two oppositely rotating propellers with the axes coincident with the axis of the fuselage. Thus in flight the axis of the fuselage is inclined from a vertical position to horizontal position. Each propeller consists of a sleeve, carrying radially located blades attached to a shaft with an axis, fixed on the axis of the fuselage inside the fuselage with a drive to control the cyclic and collective pitch of propellers.
In the above aircraft there is no empennage, while the control of angular position is carried out by creating moments on the propeller using a wobble plate to operate the aircraft and get it over under the necessary angles in flight from vertical during take-off up to close to horizontal in flight.
The advantage of the above aircraft and method of realization of flight is the use of control of cyclic step of propellers for creating moments in the set direction, as well as, for example in helicopter propellers, and in this case wobble plate is applied to control of the position of an aircraft and its propeller, including the case when the propeller axis is pointed in the direction of flight in conditions of a flow of propellers, close to the axial flow.
The drawback of the method of creation of elevating force used for flight, transversal to the axis of rotation of the propeller, when the axis is inclined under a small angle to the incident flow, for example, in the vertical plane in horizontal flight, is that in case of rotation under wide angles to the horizontal position and blades close to vertical position the forces created on blades increase the thrust of the propeller, but do not make important contribution to create the lift.
In the above mentioned engineering solution the conditions of creation of lift of sufficient value, the conditions of its adjustment and provision of absence of the phenomena of shock stall on the propeller blades are not determined. Besides the conditions allowing to achieve the absence of sectors where blades are flowed under negative angles of attack are not determined.
There is a known aircraft and method of its flight, U.S. Pat. No. 3,106,369, B64C9/38, B64C11/40, B64C29/00, B64C9/00, B64C11/00, B64C29/00 in which it is offered to use a radial force: the force transversal to axes of propellers, in horizontal flight of an aircraft with two swivelling propellers of opposite rotation mounted on a supporting girder-wing.
Besides there is known an aircraft, DE1406374, B64C29/00, B64C29/00, having four rotary propellers at the ends of tandem-type located wings, using the same method of flight.
In the above aircrafts the propellers are places on the wings which are being used as supporting girders for mounting the propellers, and also used for control and if necessary for creating additional lift alongside with propellers.
For increasing the force, transversal to the propeller axis, the inclination angle of the axis about the direction of flight is increased, and to control the value of draft of the propeller the blades installation angles are changed.
The above aircrafts perform horizontal flight at high speeds using propellers. It is reached due to incline of propellers axes from the vertical position used at low speeds, to a position when the axis makes an angle from 5° to 10° with deflection of the front end of the axis of propellers upwards in about the direction of flight, after achieving the speed of flight at which the weight of the aircraft is counterbalanced by the force, transversal to the propeller axis.
Thus each propeller creates a radial force, transversal to the axe of rotation, providing the main part of lift in flight, when the propeller axis is at an angle to the flow, and a drawing force for overcoming the resistance.
Use of blades being wide and rectangular at their roots, narrowed to the ends, allows to create the lift close to weight when achieving high transsonic speed if the propellers are directed alongside the flow.
Distribution of angles of attack to propellers is defined upon achieving the design speed of flight by the angles of installation of blades and the axis angle about the direction of the incident flow within the specified limits.
It is known, that CURTISS WRIGHT CORP has constructed a number of aircrafts based on the above mentioned patents.
In particular, an experimental vertical take-off and landing (VTOL) aircraft with two rotary propellers X-100 was built. It is a new type VTOL with rotary air propellers creating radial force in horizontal flight.
It is known, that in 1960 there was a successful flight with transition from vertical take-off to horizontal flight using the lift due to propellers mounted with their axes are directed towards the flight.
There is also a known VTOL X-19, being an aircraft with tandem arrangement of wings and four rotary propellers at the ends of wings.
It is known from specifications, that in horizontal flight the above mentioned devices use the peripheral speed of rotation of propellers characteristic for high-loaded air propellers which peripheral speed values fall within the transsonic range and this speed is not lower than the maximal speed of flight (<http://www.nasm.si.edu/research/aero/aircraft/curtiss_x100.htm>).
The drawback of these aircrafts, such as X-100, X-19 and of the method of their flight, is that achievement of radial force directed transversally to the propeller axis, becomes possible only at high transsonic speeds of flight comparable to the peripheral speed of propellers.
The drawback of the method of creation of elevating force used for flight, transversal to the axis of rotation of the propeller, when the axis is inclined under a small angle to the incident flow, for example, in the vertical plane in horizontal flight, is that in case of rotation under wide angles to the horizontal position and blades close to vertical position the forces created on blades increase the thrust of the propeller, but do not make important contribution to create the lift.
During the horizontal flight with lift on the propellers the axis angle to the incident flow of lift on propellers may vary from 5° to 10°, the conditions of use of the method, allowing to achieve the absence of the phenomena of stalling from the blades when increasing the angle of installation of blades if the angles of the axis to the flow are wider then 8° are not determined.
The conditions of use of the method, allowing to achieve the absence of sectors where the thrust reversion occurs are not determined. The use of angles of the axis of propellers close to 10°, in case of rotation of the blade upwards in horizontal flight leads to occurrence of negative angles of attack of blades that reduces the thrust of the propeller while increasing the force in the plane of propellers. This leads to unjustified expenses for overcoming the force diminishing the speed arising on blades on these areas of the propeller.
Use of smaller angles of axes to the flow, not resulting to formation of a reversal area, leads to redundant thrust when creating the lift necessary for maintaining the weight. For reducing the thrust it is necessary to reduce the angles of installation of blades of the propeller that can lead to occurrence of a thrust reversal area on the propellers.
Use of propeller operation modes having high peripheral speed with values of relative speed of the propeller less then unity if the propeller is mounted under an angle to the flow stream results in that on the ends of blades where the peripheral speed gets its greatest value, when rotating from vertical to horizontal position, to variation of angles of attack more than twice, than the variation of angles of attack at the blade root where the peripheral speed gets its least value therefore the increase of the angle of the axis the with respect to the flow is limited by increase of angles of attack at the root propeller while the end portion of the blade does not reach the maximal increase in angles of attack at blade positions close to horizontal.
Thus the drawback is limitation of the axis angle with respect to the flow direction in case of flight of an aircraft at high speeds, the phenomena of shock stall at high angles of the axis with respect to the flow and initiation of an area of thrust reversion on the propeller. The narrow range of angles of the propeller axis with respect to the flow providing the possibility of flight, complicates the transition from flight with the axes located vertically, to flight with the axes located in the direction of horizontal flight.
The method of flight of an aircraft most close to the offered invention is U.S. Pat. No. 2,738,148, B64C23/00, based on obtaining of lift on blades of propellers of an aircraft.
From the prior knowledge it is known that, when inclining the axis of propeller under a small corner with the direction of the incident flow moving at a high speed, a lift occurs. It is known as a “side force” of propeller that leads to course shift of an aircraft. When increasing the angle of attack of an aircraft to higher values there is “side force”, entailing vibrations of propeller blades. Thus the downsweeping blade creates a higher lift, than the blade in vertical position, and each upsweeping blade creates smaller lift, than the blade in vertical position. The change of lift of the blade is cyclic at propeller rotation frequency. The lift fluctuations on each blade lead to oscillations of the blade with the propeller rotation frequency, thus increasing tension in the blade. The lift increase occurs from the vertical position of the blade to the maximal value when the blade is horizontal, and drops when the blade is vertically downwards. For a propeller having three or more blades, summation of the increased and reduced vertical components of forces of blades results in steady force, normal to the propeller axis.
In the above mentioned patent it is offered to carry out horizontal flight of an aircraft using lift on the propeller. Thus the part of normal lift is created by the wing, but no more than a half of the required lift for horizontal flight.
The lift is due to propellers of opposite rotation located in pairs in front and rear from the center of weight of the aircraft. The axes of propellers are directed in the direction of flight. For making the lift on propellers in horizontal flight the aircraft is being speeded up till minimal transsonic speed and operated so that the propeller axes in vertical plane have deviated by a positive angle from 2° up to 12° to the flow.
The drawback is that propellers develop significant radial force only at high speeds of flight when speeds of flight become comparable to peripheral speed of rotation of propellers.
The drawback of the method of creating the lift used for flight, transversal to the axis of rotation of the propeller, in case of deflection of the axis under a small angle to the incident flow, for example, in the vertical plane in horizontal flight, is that when rotating under wide angles to the horizontal and blades position close to vertical the forces build on the blades increase the thrust of the propeller, but do not make significant contribution for the lift.
In horizontal flight when creating the lift on propellers the angle of the axis to the direction of incident flow may vary from 2° up to 12°, but the conditions of use of the method, allowing to achieve the absence of phenomena of shock stall on the blades when increasing the angle of installation of blades if the axis angles with respect to the flow exceed 8°, are not defined.
When using on propellers a deflection of the axis at angles of the axis with respect to the flow up to 12° the thrust sharply falls in case of negative angles of attack on blades during upward rotation in horizontal flight. Decrease in thrust and increase in force, transversal to axes of propellers, as well as the lift allows to get the flight on propellers with normal for propellers high peripheral speed of rotation, but this leads to unjustified expenses for overcoming the forces diminishing the speed, arising on the reversing portion of the propeller. The conditions of flight without sectors of power reversion are not determined.
Use of smaller angles of axes to the flow, not resulting in reversal area, results in lift necessary for maintaining the weight, the thrust value would be redundant, and for reducing the latter it is required to reduce the angles of installation of the propeller blades that may lead to negative angles of attack and the reversal area on a part revolution when at rotating the blade upwards in horizontal flight.
Use of modes of propeller with high peripheral speed having values of relative speed of the propeller of less than unity leads in case of installation of the propeller under an angle to the flow to that at the ends of blades where the peripheral speed gets the greatest value, when rotating from vertical to horizontal position, the variation of angles of attack is more than twice less, than the variation of angles of attack at the blade root where the peripheral speed takes the least size therefore the increase of the angle of the axis to the flow is limited by the increase of angles of attack at the root propeller while the end part of the blade does not reach the maximal increase of angles of attack in case of blade positions close to horizontal.
Thus the drawback is limitation of the angle of axis to the flow direction at flight of the aircraft at a high speed, the phenomena of shock stall at high angles of axis to the flow and an area of power reversion on the propeller. The narrow range of angles of axis of propeller to the flow where the flight is possible, complicates the application of this method for transition from vertical take-off with axes located vertically, to flight with the axes located in the direction of horizontal flight. Creation of a part of lift using a wing leads to additional thrust power expense for overcoming the wing resistance when all the necessary forces for flight may be created on propellers.
The main advantage of the offered methods of flight on propellers, is that creating the lift on propeller located in an axial flow allows to increase some times the flight speed on propellers, as compared to helicopters having the flight speed limited by nonuniformity of the flow of the main rotors rotated around of axes to the flight direction. Using such a method of horizontal flight is especially specific for aircrafts using the swivel of main rotors from the position with vertical axes of propellers at take-off to almost horizontal position of axes in horizontal flight and allows a vertical take-off for aircrafts vertical, in the same way, as well as a helicopter, and the flight on propellers at a speed considerably exceeding the helicopter flight speed.
The main advantage of the offered methods of flight on propellers, is that creating the lift on propeller located in an axial flow allows to increase some times the flight speed on propellers, as compared to helicopters having the flight speed limited by nonuniformity of the flow of the main rotors rotated around of axes to the flight direction. Using such a method of horizontal flight is especially specific for aircrafts using the swivel of main rotors from the position with vertical axes of propellers at take-off to almost horizontal position of axes in horizontal flight and allows a vertical take-off for aircrafts, in the same way, as well as a helicopter, and the flight on propellers at speeds considerably exceeding the helicopter flight speed.
Developing aircrafts having such a position of main rotor have some difficulties due to obtaining a sufficiently high lift regarding the thrust. There were some designs of propellers having wide root portions for increasing the radial force in flight were. However the lift, sufficient for flight at the mentioned speeds, was obtained only at high speeds of flight thus complicating the transition to flight using radial force without wing support. Using the supporting wing alongside with propellers increases the weight and resistance of the aircraft, and also results if arranging the propellers at the end of a wing, to additional oscillations in the wing design.
The main drawback of the offered methods of creating of force, transversal to the propellers axis in the axial flow, is the impossibility of creating an enough the high lift in horizontal flight, due to creating a force, being transversal to the propellers axis. A low efficiency of expenses of capacity for creating a thrust when creating a thrust on the propeller. High speeds of flight where it is possible to create a significant lift on the propellers having their directed towards the flight.
The drawback is the limitation of the angle of axis to the flow direction when flying at high speeds with the phenomena of shock stall and occurrence of an area of power reversion on the propeller. A narrow range of angles of the propeller axis to the flow and a narrow range of speeds at which creating the force, transversal to the axis of rotation of the propeller is possible, for realizing the flight complicates the feasibility of transition from vertical position of axes of propellers at take-off to horizontal flight with axes of rotation of propellers alongside the flight direction.
Besides, the conditions of use of the method allowing to achieve the absence of shock stall on the blades are not determined, the conditions of use of the method allowing to achieve the absence of sectors of the power reversion are not determined as well.